Don't crash on EINTR
Workaround for [*].

We should probably also somehow require a libcurl built with async dns resolver, as with
this option set we may get stuck if libcurl is built with the default synchronous resolver.

*:  http://stackoverflow.com/questions/9191668/error-longjmp-causes-uninitialized-stack-frame

Conflicts:
	src/modules/curl.c